From fe0c935a6cbf25d72a27c7a345df8a2151de0b74 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 30 Apr 2007 15:09:51 -0700 Subject: rework pm_ops pm_disk_mode, kill misuse This patch series cleans up some misconceptions about pm_ops. Some users of the pm_ops structure attempt to use it to stop the user from entering suspend to disk, this, however, is not possible since the user can always use "shutdown" in /sys/power/disk and then the pm_ops are never invoked. Also, platforms that don't support suspend to disk simply should not allow configuring SOFTWARE_SUSPEND (read the help text on it, it only selects suspend to disk and nothing else, all the other stuff depends on PM). The pm_ops structure is actually intended to provide a way to enter platform-defined sleep states (currently supported states are "standby" and "mem" (suspend to ram)) and additionally (if SOFTWARE_SUSPEND is configured) allows a platform to support a platform specific way to enter low-power mode once everything has been saved to disk. This is currently only used by ACPI (S4). This patch: The pm_ops.pm_disk_mode is used in totally bogus ways since nobody really seems to understand what it actually does. This patch clarifies the pm_disk_mode description. It also removes all the arm and sh users that think they can veto suspend to disk via pm_ops; not so since the user can always do echo shutdown > /sys/power/disk, they need to find a better way involving Kconfig or such. ACPI is the only user left with a non-zero pm_disk_mode. The patch also sets the default mode to shutdown again, but when a new pm_ops is registered its pm_disk_mode is selected as default, that way the default stays for ACPI where it is apparently required. Signed-off-by: Johannes Berg Cc: David Brownell Acked-by: Pavel Machek Cc: Cc: Len Brown Acked-by: Russell King Cc: Greg KH Cc: "Rafael J. Wysocki" Acked-by: Paul Mundt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/main.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/power/main.c') diff --git a/kernel/power/main.c b/kernel/power/main.c index 3062e940d1f..053c0a7d7f5 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -30,7 +30,7 @@ DEFINE_MUTEX(pm_mutex); struct pm_ops *pm_ops; -suspend_disk_method_t pm_disk_mode = PM_DISK_PLATFORM; +suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN; /** * pm_set_ops - Set the global power method table. @@ -41,6 +41,10 @@ void pm_set_ops(struct pm_ops * ops) { mutex_lock(&pm_mutex); pm_ops = ops; + if (ops && ops->pm_disk_mode != PM_DISK_INVALID) { + pm_disk_mode = ops->pm_disk_mode; + } else + pm_disk_mode = PM_DISK_SHUTDOWN; mutex_unlock(&pm_mutex); } -- cgit v1.2.3